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在植物线粒体和叶绿体转录本上,数百个胞嘧啶(C)位点经脱氨基反应变为尿嘧啶(U),这是一种在转录本水平上对遗传信息进行修饰或调控的机制.在植物细胞器中,RNA编辑过程需要不同家族的RNA编辑因子相互作用组装成复杂的编辑复合体,特异地识别编辑位点进行编辑.最初的研究发现,植物RNA编辑受到高特异性五环肽重复(pentatricopeptide repeat, PPR)蛋白的调控,目前在植物中发现400多种PPR家族蛋白,编辑作用复杂.之后对RNA编辑因子互作蛋白/多细胞器RNA编辑因子(RNA editing factor interacting proteins /multiple organellar RNA editing factors,RIP/MORF),细胞器RNA识别基序(organelle RNA recognition motif,ORRM),细胞器锌指蛋白(organelle zinc-finger,OZ)等的研究表明,这些非PPR蛋白组分可以与PPR蛋白形成编辑复合体,共同参与编辑,且RNA编辑复合体具有多样性.RNA编辑因子的缺失会引起植物的生长发育受阻,果实成熟延迟等,对RNA编辑因子的研究显得尤为重要.对植物中RNA编辑因子的功能及其作用机制研究进展进行综述,旨在为后续RNA编辑的研究提供一定的参考. 相似文献
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Pentatricopeptide repeat (PPR) proteins with an E domain have been identified as specific factors for C to U RNA editing in plant organelles. These PPR proteins bind to a unique sequence motif 5′ of their target editing sites. Recently, involvement of a combinatorial amino acid code in the P (normal length) and S type (short) PPR domains in sequence specific RNA binding was reported. PPR proteins involved in RNA editing, however, contain not only P and S motifs but also their long variants L (long) and L2 (long2) and the S2 (short2) motifs. We now find that inclusion of these motifs improves the prediction of RNA editing target sites. Previously overlooked RNA editing target sites are suggested from the PPR motif structures of known E-class PPR proteins and are experimentally verified. RNA editing target sites are assigned for the novel PPR protein MEF32 (mitochondrial editing factor 32) and are confirmed in the cDNA. 相似文献
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Isolation of total RNA from Arabidopsis thaliana seeds 总被引:12,自引:0,他引:12
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Derrick Watkins Gerald B. Koudelka Loren Dean Williams 《Journal of molecular biology》2010,396(4):1145-1279
The binding of proteins to specific sequences of DNA is an important feature of virtually all DNA transactions. Proteins recognize specific DNA sequences using both direct readout (sensing types and positions of DNA functional groups) and indirect readout (sensing DNA conformation and deformability). Previously we showed that the P22 c2 repressor N-terminal domain (P22R NTD) forces the central non-contacted 5'-ATAT-3' sequence of the DNA operator into the B′ state, a state known to affect DNA hydration, rigidity and bending. Usually the B′ state, with a narrow minor groove and a spine of hydration, is reserved for A-tract DNA (TpA steps disrupt A-tracts). Here, we have co-crystallized P22R NTD with an operator containing a central 5′-ACGT-3′ sequence in the non-contacted region. C·G base pairs have not previously been observed in the B′ state and are thought to prevent it. However, P22R NTD induces a narrow minor groove and a spine of hydration to 5'-ACGT-3'. We observe that C·G base pairs have distinctive destabilizing and disordering effects on the spine of hydration. It appears that the reduced stability of the spine results in a higher energy cost for the B to B′ transition. The differential effect of DNA sequence on the barrier to this transition allows the protein to sense the non-contacted DNA sequence. 相似文献
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应用Gupta等和Tanaka等建立的RNA序列双向直读技术,并辅以部分酶解法、化学法等,测定了芹菜叶细胞质的5SrRNA的全序列:与菠菜和蕃茄细胞质已知5SrRNA序列进行了比较,发现它们之间在序列上有高度的保守性。 相似文献